Tire pressure signal



S. G. BOND Dec. l2, 1939.

T IRE PRESSURE S IGNAL 2 Sheets-Sheetl l Filed March '7, 1938 INVENTOR. SHERMAN G. BOND BY @www QQWVQM ATTORNEY.

Dec. 12, 1939. s. G. BOND 2,183,089

TIRE PRESSURE SIGNAL Filed March 7, 1938 2 Sheets-Sheet 2 vill/1111111111 n l O en az A es `I I l S5 19 65 I 1E y INVENTOR.

SHERMAN G. BOND BY Z W AATTORNEY.

Patented Dec. 12, 1939 UNITED STATES PATENT OFFICE A TIRE PRESSURE SIGNAL Sherman G. Bond, Wichita, Kans.

Application March 7,

4 Claims.

This invention relates in general to tire pressure signals and particularly to that class of device in which means are employed in connection with each tire for indicating a decrease from normal pressure in sai-d tires, the indi- Gator being in visual relation to the operator of the vehicle.

This invention contemplates improvements over the device shown in my Patent No. 1,773,215, entitled Tire indicator switch, granted August 19, 1930.

'I'he primary object of the invention is to provide an actuator rotatable with the tire and responsive to changes of pressure within said tire, a circuit closing device in close proximity to the circular path of the actuator and adapted to be intermittently actuated by an element on said actuator when the pressure in the tire decreases a predetermined amount.

Second; to provide a signalling circuit including spark coils and a visual indicator comprising spark gaps for each tire, the momentary closing of the circuit causing a spark to jump the gap and indicating to the vehicle operator that a tire is losing pressure. The circuit includes the storage battery of the vehicle or an auxiliary source of current for the spark coils, the conductor from the battery passing through the ignition switch whereby the tire signal will operate only when the ignition switch is on, eliminating the possibility of running down the battery if one of the actuators should be stopped in alignment with the circuit closing device. A separate circuit including a spark coil, signal, actuator and circuit maker is provided for each tire, whether on a standard passenger car or truck with one tire on each wheel, or on other vehicles using dual wheels and tires, the operator being enabled to tell instantly exactly which tire is losing air.

Third; to provide an improved construction in the actuator making it extremely sensitive and less susceptible to damage and deterioration by the weather and elements.

Fourth; to provide an improved construction in the circuit closing device whereby more sensitive adjustments may be made and smoother operation effected.

In perfecting a successful device of this nature it has been found that two essential features or characteristics are required. These are, rst, an actuator or pressure responsive member which is adjustable and sensitive to high degree, that is, within a pound or two of the -desired tire pressure, whereby the device will op- 1938, serial No. 194,286

(C1. 20o-5s) erate a signal when the pressure in any tire has dropped from l to 5 pounds below the required pressure. This is the preferred range but the adjustment can be set so as to operate at any desired pressure below normal. The adjustable ,5 feature makes it possible to use the same actuator with equal efficiency on heavy duty Ytires requiring 100 pounds or more pressure or on loW pressure balloons of 20 to 30 pounds pressure.

In carrying out this rst feature of my device I have so designe-d it that there will be little or no friction on the moving parts actuated by the air pressure since any friction will retard the free movement of the mechanism.

The second feature which must be inherent in a successful operating device of this nature is a positive acting signal. Since the Contact between the actuator and the circuit closer'is intermittent and momentary, an instantaneously actuable signal or alarm system must be Vprof vided. It has been found that incandescent bulbs, bells, buzzers and the like willvv not operate successfully due to the lag in the circuit caused by the resistance thereof and the tooshort period of Contact in the circuit closing device. However, in a circuit employing spark coils and a spark gap, the response to the briefclosing or" the circuit is instantaneous and a spark will jump the gap every time the circuit is closed, making a positive and very noticeable alarm or signal for the operator.

The actuator is in permanent communication with the inner tube of thetire so that the pressure is equalized and any changes in pressure in the tube instantly cause an equal change of pressure in the actuator.

Further objects and advantages of my invention, as well as its construction and operation will be readily apparent by reference to the following specication in connection with the accompanying drawings in which:

Fig. '1 is a semi-diagrammatic top view of a vehicle chassis showing the arrangement and circuit of the tire pressure signal comprising my invention. l 45 Fig. 2 is a top View of the dash board signal assembly.

Fig. 8 is a front elevational view of the same.

Fig. 4 is a fragmentary, cross sectional View through a wheel and brake drum showing the' actuator and the circuit closer in elevation with parts broken away to better illustrate certain other parts. f

Fig. 5 is a detail cross sectional View through the composite valve stem showing the outlet to the actuator.

Fig. 6 is a detail longitudinal, sectional view through the actuator.

Fig. '7 is a longitudinal, elevational View of the same.

Fig. 8 is a detail cross sectional view through the circuit closing device.

Fig. 9 is an elevational view in detail or the interior of the circuit closing device with the cover broken away in section.

Fig. 10 is a fragmentary elevational View of a portion of a tire showing the actuator in communication with the inner tube through the composite valve stem.

Referring now to the drawings by numerals of reference l designates a vehicle chassis carrying wheels 2, brake drums 3 and brake echanism covers ll, my invention being applied to these above-named parts.

The visual indicator system includes conductor`s`5 running from each wheel to one of the 'sparky points 6, each of the spark points E with the points Si, forming the spark gap, the points being connected to spark coils i' thr ugh conductors l', a common conductor 8 connecting the other side of each spark coil and passing through switch 9 t0 the storage battery it?, the other side of which is grounded. The switch is preferably the ignition switch so that the signal device will operate only when the ignition switch is turned on. The circuit closing mechanism will be described more in detail hereinafter. The spark points comprising the visual indicator assembly may be suitably mounted on the instrument panel of the vehicle or on the steering column in visual relation to the operator of the vehicle.

In Fig. 4 is shown a fragmentary View of the Wheel 2, brake drum 3 and brake cover li, the actuator Il being secured to the wheel and the circuit closing device l2 being secured to the brake cover l 4in a suitable position so as to be in actuable relation to the actuator. The device as shown in Fig. 4 indicates that the circuit is closed.

In employing my device on vehicles it is necessary to provide means for interconnecting the inner tube with the actuator ll and toward that end I have provided in connection with the valve stem I3 having valve core ld, a valve opening member l5 threadedly engaging said stem and having a valve engaging ringer it adapted to contact the valve pin il and force same down to open the valve. The ringer l5 is adjustably threaded into the member l5 and has passage i8 therein through which the air may pass when the valve is open.

A T-head I9 is secured to the member l5 by means oi the coupling member 2u threaded on member l5, packing '2l forming an air tight cennection. A valve core 22 is positioned in T-head IG and valves the passage in communication with passage 24 leachng to passages i3 in valve engaging finger it. An offset extension has Ypassage 26 opening into passage 2li, said oliset suitably carrying flexible hose connection l to actuator Il.

Air to the inner tube is applied at the end 28 of the T-head l5 and it is evident that the valve 22 is suflicient to valve the tube and the valve core I4 may be removed. However in assembling my tire pressure signal it may be desired to apply it directly on the existing valve stems without removing the cores and for that reason I have provided the engaging nger l@ which retains the valve core i4 in open position.

'aieaoee The actuator ll comprises an elongated body member or housing 29 having attachment lugs 3K! for securing the actuator t0 the wheel. Positioned in one end of the body member 29 is a pressure responsive member orresilient sac 3| encircled by a highly resilient coil spring 32 having head ria-nge 33 and plate secured thereto. The head flange 33 is threadedly secured in cap 35 which in turn is threadedly engaged on housn ing The cap 35 carries a seat 3G in which integral ring collar 3l of sac ti may rest. A nozzle cap Il@ is in threaded connection with cap 35 and has an annular V offset liti which engages and forms an air tight connection with the collar 3l', a washer @El forced against the inside of the collar 3l' by the cap also assisting in forming an airtight connection. A passage lll is provided through the nozzle cap 3S and the washer connecting with the interior of the resilient sac Sil. The hose connection 'il' is suitably sen cured to the nozzle cap lill, the other end oi the hose connecting with the extension on the Phead lll.

Adapted to abut the plate Sil is the plunger head l2 secured to the end of the plunger or stem B sleeved in bearing cap lil in threaded engcrnent with the housing fill. An interior tl 'ead provided in the housing and an adjustment ring is carried by said threadl and bears against the compression spring fil which encircles the plunger ll, sp1 il bearing against the plunger head 32, the plunger movinU freely in the adjustment ring fili. Packing if sxrroundsthe plunger where it passes through extension Lit of bearing cap lit, a packing plug being threadedly engaged in the extension fili and adapted to be tightened the packing. l

A contact arm 5l, preferably oi a non-conducting material and curved as shown, is pivoted at 52 to extend` lugs Links are pivoted to the arm 5l at 55 and to plunger arm il@ at lil, plunger arm being secured to the plunger i3 by screw or any other suitable means, the rib of arm 56 being positioned in the slot il@ or", the plunger preventing turning of the plunger.

As shown in iig. 7 the tail ofthe contact arm may be curved to approximately follow the circular path oi' the actuator ll as it rctates with the wheel.

From the foregoing detailed specii'ication ol' the actuator it will be seen that the resilient sac 3i forms an elongatable airfchamber in direct cornrnunication with the interior ci' the inner tube through the hose Connection The moving parts are constructed and arr ged to provide extreme freedom of movement muni protection rain, foreign elements.

rBurning the adjustment ring lli to compress or and with maXi dust and other elong the spring Il? will change the setting of the device, that the position or" the ring lli and amount ci compression on the spring will determine the point which the loss of air pressure in the tire will cause movement in the actuator. f

The circuit closing device l2 shown in Figs. 4, 8 and 9 comprises a casing and cover and mounting plate suitably secured thereto. A transverse rock` shaft passes through insulator bearings S5 in the casing and has an out side rocker arm carrying a pivoted segment il preferably oi a non-conductive material and adapted to be contacted by the contact arm 5! 'oi the actuator il.

the other end of the l iii) A resilient arm 68 is secured to the rock shaft 64 and has a loop 68 for greater resiliency, the

free end of arm 68 carrying contact point le? adapted to engage the contact point 'il on resilient arm l2 secured to casing 62 at '13. An adjustment screw 'it threaded in casing 62 bears against the arm 'l'l and provides for adjustmer o-f the point 'El carried thereby.

The rock shaft carries a pin l adapted to be engaged by adjusting screw l, the end of which carries an insulated segment il to prevent grounding of the rock shaft, adjusting screw "it also being used for setting the gap between the points 'Iii and ll.

The points are kept separated by means of coil spring '18, one end of which is secured to the spring pin 'I3 on roclr shaft 66, the other end of the spring being carried by loop 8d of terminal 8l passing through insulator 82 in casing 62, the conductor 5 beingconnected to the terminal 3l.

The ears or lugs on mounting plate 63 provide for attachment or" the circuit closing device to the brake mechanism cover plate l or to any other suitable support, it being kept in mind that the segment tl' must be positioned in the path of the contact arm 5l of the actuator Il when the arm is moved by `decrease of pressure in the tire.

It will be seen from the preceding specifications that the contact point lil is insulated from the ground side of the circuit and when the contacts are closed the circuit is made through the casing lit to ground, and since one side of the battery is grounded the current will pass through the proper coil 'l and cause a spark to jump the gap formed by points and G.

With the actuators l! properly secured to each wheel and the circuit closing devices i2 suitably mounted to each brake cover 4, and T cap assemblies on each valve stem it, the air hose connection 27 is fastened to the nozzle cap 38 and the oiset extension E5 of the T-head i9.

The proper amount or air is pumped into each tire, the pressure equalizing itself throughout the inner tube and the actuator, the pressure responsive member or resilient sac Si within the coil spring jacket 32 elongating to force plunger 153 outwardly and causing the curved contact arm 5l to move toward the actuator housing 29, where said arm 5l will clear the segment 6l on the rocker arm 65. As long as the pressure in the tire and in the sac 3l remains constant and above a predetermined amount, the contact arm 5l will retain its position. However, if a leak occurs and air is lost, the sac 3l will contract or shorten, causing outward movement of the contact arm 5l moving it into intermittent engagement with the segment iil to move the points 'IB and 'il into circuit closing engagement with each other, causing a spark to `iurnp the gap in the visual signal corresponding to the tire which is losing air,l the operator oi the vehicle being instantly apprised of the fact that the tire is deiicient in air pressure.

Adjustment of the ring il@ in the actuator will change the compression on the spring il to allow the sac 3l to react at a predetermined air pressure. The spacing 'of the points 'lli and 'il and the relation between .the segment G7 and the contact arm 5l may be adjusted for most suitable operation.

From the foregoing it will be apparent that I' have provided an eiciently'and positive operating tire pressure signal including visual indicator means whereby the vehicle operator may be instantly apprised of a low tire.

Past records show that countless numbers of accidents have occurred due to low tires blowing out. Life of tires are greatly shortened when they are underiniiated. In trucks and busses having dual wheels, it is often true that pressure is lost in one of the tires, throwing a great overload on the other tire. This has caused blowouts with attendant disastrous and ofttimes tragresults. By use of my device, however, the fact that the air pressure is low will be immediately conveyed to the operator who can take the necessary precautions until repairs are made or the pressure brought up to normal.

it is obvious that changes in form, proportion and details of construction may be resorted to without departing from the spirit of my invention and I therefore reserve all rights to such changes as come within the scope of these specincations and the following claims.

What l claim as new and desire to'secure by Letters Patent is:

in a device of the class described, an elongated casing,v a pressure responsive element in the a plunger` movable by the pressure responsive element and slidably extending through and sealed with respect to one end of the casing, a Contact ann pivotally carried at one end by the casing, said plunger being pivotally connected to said Contact arm to cause movement thereof with respect to the longitudinal axis of the casing.

2. In a device or the class described, an elongated casing, a pressure responsive element in the casing, a plunger movable by the pressure responsive element and slidably extending through and sealed with respect to one end of the casing, a contact arm pivotally carried at one end by the casing, a link pivoted to the plunger to the contact arm to cause movement of said contact arm toward and away from the longitudinal axis o1 the casing upon endwise Inovement of the plunger.

ln a device of the class described, an elongated casing, a pressure responsive element in the casing, a plunger movable by the pressure responsive element and slidably extending through and sealed with respect 'to one end of the casing, a contact arm pivotally carried at one end by the casing, an arm carried by the plunger, a link pivoted to the plunger arm and to the contact arm to cause movement of said Contact arm toward and away from the longitudinal axis oil the casing upon endwise movement of the plunger.

ll. ln a device of the class described, an elongated casing, a pressure responsive element in the casing, a plunger movable by the pressure responsive element and slidably extending through and sealed with respect to one end of the casing, a contact arm pivotally carried at one end of the casing, said plunger being pivotally connected to said contact arm to cause movement thereof with respect to the longitudinal axis of the casing, saidy pressure responsive element including a rubber' sac, a peripheral flange on one end of said sac, a seat for said ilange, a nozzle tip carried by the casing, and a V-shaped sealing flange carried by said tip and adapted to engage the flange on said sac to force said flange into sealing engagement with the seat.

SHERMAN G. BOND. 

